Expansion and amplification of weak randomness with untrusted quantum devices has recently become a very fruitful topic of research. Here we contribute with a procedure for amplifying a single weak random source using tri-partite GHZ-type entangled states. If the quality of the source reaches a fixed threshold R=41log2(10), perfect random bits can be produced. This technique can be used to extract randomness from sources that can't be extracted neither classically, nor by existing procedures developed for Santha-Vazirani sources. Our protocol works with a single fault-free device decomposable into three non-communicating parts, that is repeatedly reused throughout the amplification process.
@article{arxiv.1305.0990,
title = {Device-independent randomness amplification with a single device},
author = {Martin Plesch and Matej Pivoluska},
journal= {arXiv preprint arXiv:1305.0990},
year = {2014}
}